A work vehicle represented by an HST (hydro static transmission) vehicle includes a reducing device in which a reducing agent cleans exhaust gas exhausted from an engine. There is a known configuration that starts restricting the engine rotational speed when the quantity of remaining reducing agent is smaller than or equal to a predetermined threshold and lowers the engine rotational speed to a low-idle speed to prevent high-power operation.
Patent Literature 1 discloses a configuration that prevents an engine from stalling when the work vehicle starts restricting the engine rotational speed.